The people who reported issues were using either a 6200TC or a 7300GS. Boththe 6200TC and the 7300GS are equipped with TurboCache support. More advanced Nvidia boards (6200 non-TC, 6600, 6800, 7600, ..) don't support TurboCache it is only used on various lowend boards (I think on 7100/7200 cards aswell). As I mentioned I'm using a rd480 with a 6600gt and don't have issues, the same for someone who moved from a 7300GS to a 6600.

I think the issues only appear for cards using TurboCache. I don't know this for sure but based on my result combined with the results of a user who moved to a 6600, it seems to be related.

Thanks for the info. However, I just checked the specs for the 6600 based cards
on the Nvidia website, and it shows that TurboCache is used. So, it appears that
it is some other reason behind the incompatibility. Maybe Lonni could elaborate
on the technical issue (note: I'm not asking for a resolution date) and let us all
know what's the reason behind this incompatibility that occurs only under Linux. Back when I was using the 7300 based card, it worked fine under WindowsXP but it didn't work at all with the Nvidia drivers while running Linux....